Ultrasonic testing system and method for ceramic honeycomb structures

Both a system and method for detecting the presence or absence of internal discontinuities or inhomogeneities in a fired or green ceramic honeycomb structure is provided. The system includes a membrane disposed over a surface of the honeycomb structure, at least one ultrasonic transmitter that engages the membrane and transmits ultrasonic waves into the honeycomb structure, a translation assembly connected to the ultrasonic transmitter for sliding said transmitter across said membrane in a predetermined pattern, and an ultrasonic receiver that receives a modulated response from the ultrasonic waves transmitted into the honeycomb structure. The membrane is preferably plastic sheet material, such as polyester, having a temporary adhesive on one side and a thickness that is about one-quarter of the wavelength of the ultrasonic waves in order to avoid attenuation of the modulated response. In the method, the plastic sheet material is applied over the surface of the honeycomb structure via the temporary adhesive and the ultrasonic transmitter is simultaneously actuated while the translation assembly continuously slides the ultrasonic transmitter over the plastic sheet material in a predetermined scanning pattern.